This invention relates to plumbing designs for bathtubs. Bathtubs typically have overflow drains which prevent the bathtub from being filled beyond a certain level. These overflow drains prevent the overflow of water from the bathtub and its resulting damage.
Currently, a multiple-piece waste and overflow unit is connected to the overflow and bottom drains of a bathtub. This multiple-piece waste and overflow unit comprises overflow and bottom connectors for attachment to the overflow and the bottom drains respectively, pipes attached to both of these connectors, and an additional elbow or ell to connect the two pipes together. Most bathtubs have an "overflow" wall, where the overflow drain is located, that is inclined at approximately between 86.degree.-88.degree. measured from the floor to the back side of the overflow wall. Moreover, increasingly the new style of bathtub have their overflow wall angle varying even more from perpendicular, i.e., the angle is below 86.degree.-88.degree.. The construction of previous art forces the overflow to connect to the sanitary T at 90.degree. resulting in torque leading to a poor fit into the Sanitary T.
With respect to the overflow connector and its connection to the overflow drain, a rubber gasket is typically interposed between the overflow connector and the back of the bathtub and thus is used as a seal. In order to hold both the overflow connector and the rubber gasket against the bathtub, a screw is placed through an overflow cover plate and then is connected to the overflow connector, which contains a threaded hole for the screw connection. This connection mechanically holds both the overflow connector and the rubber gasket to the back of the bathtub and also mechanically holds the overflow cover plate against the bathtub water-holding surface. The problem associated with this prior art overflow connection is that the rubber gasket seal may be installed off center, can be over tightened resulting in cracking, may deteriorate overtime or may become loose such that water flowing through the overflow drain will leak and subsequently cause damage. In particular, children may loosen the overflow cover plate by playing with the overflow lever. Additionally, if the overflow connector is accidentally disattached, it is difficult to repair because of the inaccessibility to the multi-piece waste and overflow unit since most bathtubs have no trap door access to reach the waste and overflow unit after installation.
With respect to the bottom connector and its connection to the bottom drain, a rubber gasket is also interposed between the bottom connector and the bottom of the bathtub and thus is used as a first seal. The inner wall of the bottom connector is threaded so that a threaded strainer can be screwed into the bottom connector. But before the threaded strainer is mechanically connected to the bottom connector, plumber putty is placed on the underside of the trim of the threaded strainer to provide an additional second seal. Thus, this connection holds the bottom connector, the rubber gasket, and the threaded strainer to the bottom drain hole of the bathtub. However, this bottom drain connection has three disadvantages. First, since typically the multiple-piece waste and overflow unit, including the bottom connector, is made out of plastic while the threaded strainer is made out of metal, the threaded strainer will expand and contract when its temperature increases and decreases, respectively. When the threaded strainer expands, so does the plastic bottom connector and eventually the plastic bottom connector will crack and cause leaks. Second, if a plumber wants to replace a rusted strainer, the replacement process is time consuming because [1] the plumber must disrupt the mechanical connection and the two seals before installing a new strainer and [2] since the threaded strainer mechanically holds the bottom connector against the bottom drain hole, once the rusted strainer is removed, the bottom connector will move downward and away from the bottom drain hole so as to make the connection of the new strainer to the bottom connector more difficult because there is no trap door access to the bottom connector. And third, the prior art bottom connectors are designed such that only a normal connection between the multi-piece waste and overflow unit and the bathtub is possible. In the normal connection, the T-joint or sanitary tee is not directly below the bottom drain hole. Typically, this type of connection provides a poor draining rate and is susceptible to clogging.
Furthermore, the prior art multi-piece waste and overflow units require that during installation a "flood" test, which tests the plumbing connection to the overflow drain hole for leaks, must be performed separately from, not simultaneously with, a "top-out" test, which tests the plumbing connection to the bottom drain hole for leaks. The reason is that the overflow drain hole must be covered with a test plug during a top-test. If the prior art unit is attached to the bathtub at both the overflow and bottom drain holes, the top-out test cannot be performed because the overflow connector of the prior art unit relies on the screw and the overflow cover plate to mechanically hold it against the bathtub; thus, the overflow cover plate blocks or prevents the insertion of a test plug into the overflow drain hole. As a result, to perform the top-out test, only the bottom connector of the prior art unit is mechanically attached to the bottom drain hole. Therefore, top-out and flood tests cannot be performed simultaneously during mandatory plumbing inspection because the overflow connector is not attached to the bathtub. Accordingly, plumbing inspection is time consuming because after the top-test is performed, the inspector must remain or return at another time and wait for the installation of the overflow connector and cover plate so that a flood test can be performed.
Moreover, these waste and overflow units are not readily adaptable to special structural problems caused by difficult floor and wall spacings such as silent floor systems or doubled-up joists located directly behind the bathtub.
It is desired to have a plumbing design for a bathtub that avoids the disadvantages and problems of the prior art systems.